Undervoltage trip and lockout



Sept. 4, 1951 c. J. YARRICK UNDERVOLTAGE TRIP AND LOCKOUT 4 Sheets-Sheet 1 Filed April 6, 1948 INVENTOR.

BY Clea/Lia yak/tick P 1951 c. J. YARRICK 2,566,866

UNDERVOLTAGE TRIP AND LOCKOUT Filed April 6, 1948 4 Sheets-Sheet 2 INVENTOR.

B Chwdu a/vu'c/a 4 p 1951 c. J. YARRlCK 2,566,866

UNDERVOLTAGE TRIP AND LO CKOUT Filed April 6, 1948 4 Sheets-Sheet 5 INVENTOR.

BY Chwdfwfljlww'c/e Gila/new Sept. 1951 c. J. YARRICK 2,566,866

UNDERVOLTAGE TRIP AND LOCKOUT 4 Sheets-Sheet 4 Filed April 6, 1948 IN VEN TOR.

cnwda 9. 9mm BY WCAM dttm/ney/J Patented Sept. 4, 1951 UNDERVOLTAGE TRIP AND LOCKOUT Charles J. Yarrick, West Collingswood, N. J., as-

signor to I. T. E. Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application April 6, 1948, Serial No. 19,307

3 Claims. 1

My invention relates to an undervoltage lockout trip and more particularly relates to a novel undervoltage lock-out trip in which a unitary structure, including an operating mechanism, functions to both operate and lock-out the contacts until normal voltage conditions are restored.

In the operation of undervoltage lock-out mechanisms, it is desirable that the circuit breaker be operated in response to a drop in voltage, be tripped to open the circuit and remain locked out until proper voltage conditions are restored in the circuit. Heretofore this has been achieved with separate units, one operating in response to voltage conditions for tripping the circuit breaker and another unit for locking and unlocking the circuit breaker.

I have provided a novel'construction in which the circuit breaker is interrupted in response to a drop in voltage, automatically locks itself open while abnormal voltage conditions continue and automatically releases its self lock in response to restoration of normal voltage conditions, all in a unitary structure.

Accordingly an object of my invention is to provide a novel operating magnet arranged in response to a drop in voltage for effecting dis engagement of the contacts and locking them out and operating in response to a restoration of the voltage to normal conditions for releasing the locking mechanism in preparation for reclosing.

These and other objects of my invention will become apparent from a detailed description of the apparatus in connection with the drawings in which Figure 1 is a side elevational viewof a circuit breaker embodying my novel undervoltage mechanism.

Figure 2 shows the position of the mechanism with the contacts locked open.

Figure 3 shows the position of the mechanism when the contacts 39-39 are disengaged but the mechanism in a condition to permit the closing of the circuit breaker.

Figures 4 to 7 are schematic illustrations showing just sufficient parts of my mechanism to illustrate the position of the parts for the conditions in which the contacts are opened, locked out, and ready to be reclosed.

Figure 4 schematically shows the conditions of all parts with the circuit breaker closed.

Figure shows the parts, with the circuit breaker tripped open and locked out and with the contacts not yet in full open position.

Figure 6 shows the parts in full open position with the armature partially restored toward its pole face in preparation for re-energization when full voltage is restored, and

Figure 7 shows normal voltage restored and the latch removed in preparation for reclosing the circuit breaker.

Referring now to the drawings, an operating magnet 10 connected across the line [1-11 of the circuit to be protected and therefore responsive to its voltage is provided with an armature I2 which is pivoted at l3. A tension spring l4 extends from a lug IS on the armature l2 to a lug IS on the member I! and provides, as will appear more clearly hereinafter, a flexible connection driving between armature l2 and member ll. Member H, which is also pivotally mounted on the pin l3 and is provided with an extension l8 through which, as will appear hereinafter, movement of armature I2 is transferred to operate the locking mechanism and. through which operating power is transferred back to the armature for partially restoring it towards its pole face after the circuit breaker has been tripped in preparation for restoration in response to normal voltage line conditions.

For the purposes of tripping the circuit breaker in response to a drop in voltage, a link 2| secured at one end through a pin 22 to the member I! is provided with a slotted end as shown at 20 in which rides a pin 23 carrying the link member 24. The opposite end of the member 24 engages and operates a trip bar 25 of the circuit breaker,

as for example shown in Patent No. 2390735.

Rotation of the trip bar 25 in a clockwise direction, causes the circuit breaker trip latch 5| to rotate clockwise and release the locking arm 52. Release of the locking arm 52 permits the contact opening spring 30 to collapse the over center toggle 54-55. Collapse of the toggle 54-55 and the bias of the contact opening spring 30 will rotate the arm 56, which is rigidly attached to the fixed pivot 40 in a counter clockwise direction. Arm 56 being rigidly attached to the same shaft 40 that supports the movable contact arm 31, will cause the movable contact arm 31 to rotate counter clockwise and open the circuit breaker (Figure 5).

The collapse of the locking arm 52 and the toggle 54-55 causes the dog leg closing arm. 59, through the link 58 to rotate clockwise and place the handle 60 in a position to reclose the circuit breaker.

Member i! engages one end of a torsion spring 28 carried. on the pin [3, the other end of which "energize magnet id.

3 spring 28 engages the undersurface of a latching member 29, also pivotally mounted about the pin I3. Torsion spring 28 thus biases latch member 29 in a, counterclockwise direction into engagement at its front edge 12 with the pin 31 on which is pivotally mounted an inverted V-shap'ed member 32. Member 32 is movable about pin 26 as a center. Extending from the pin Si is the link 33 having a slot at its upper end at 34 in which rides a pin 35 in turn carrying the connecting link 36 connected to the movable contact arm 31 through theiixed pivot 40. Movable contact arm 37 carries the movable contact 38, which is biased open in alcounterclockwise direction by the contact opening spring 30, and which engages and clisengages the fixed contact 39 of the circuit breaker. When cone tact 38 moves to disengaged position, it operates through link 36 to move pin downwardly, in turn permitting link 33 to drop and carry pin 35 and member a clockwise rotation about pivot 26.

In normal conditions with the voltage of the line correct and the circuit breaker contacts closed, link has been rotated to its maximum clockwise position and through pin raised link 33 to its elevated position as shown in Figures 1 and l. With suchnormal conditions the winding of the magnet it is energized and the armature i2 is held against its pole face against the biasing action of the spring Hi and the overcenter tension spring ii extending from the pin 43 to pin 8i which provide a bia in a countenclockwise direction for the member ll, which counterbias tends to in turn through the tension spring M bias the armature 82 away from the magnet. However, the energizaticn of the magnet at this time overcomes this spring biasing action.

When the voltage on the line drops below a predetermined value, the current through the magnet it drops sufficiently to partially de- Arinature I 2 in response to the de-energization of the magnet ii? is now operated by action of spring il and'through spring Hi to its de 'energized position shown in Figures 2 and 5. As a result of the operation of the armature it to its ole-energized position about its pivot in a countercloclnvise direction under the biasing action of spring ii. the member ii is also rotated counterclockwise about its pivot it and the link 2! i moved'to the right, rotating the link 2 in a counterclockwise direction to trip the circuit breakers to the open position as schematically shown in Figure 5.

The movement of the movable contact" arm 37 to its trip position has in turn rotated the link 33 counterclockwise until pin 35 engages the lower end of the slot 3t in link 33 causing link 83 to be moved until it passes beneath the front edge 42 of the latching member In this position the underedge it of the latch member 29 moves over the upper edge of the pin 3! under biasing action of spring 28 and the contacts are locked out of engagement.

It will be noted at this point that the projection is of member ii is limited in its travel by its engagement with the lower end it of the member 32 as shown in Figures Zand 5. The circuit breaker is now in disengaged position.

During the continued movement of the movable contact to open position from the position shown in Figure to the complete open position shown in Figure 6, the member 32 in the course of its counterclockwise rotation has rotated link time is not restrained by spring 4! since the pin the, spring i4 permits the armature rotated in a clockwise direction about its pivot to the position shown in Figure 6 where the armature air gap is reduced in preparation for reeenergization in response to restoration of normal line voltage. The condition with the circuit breaker open and locked open now continues until normal voltage on the line is restored.

When normal line voltage conditions again obtain, the electromagnet i0 is energized suffi- -ciently to operate its armature i2 in a clockwise direction about its pivot l3 until the armature engages the pole piece of the magnet. Movement of armature I2 act through its spring 14 to rotate member ii in a clockwise direction. Member ii in turn-through torsion spring 28 rotates latch member 29 out of latching engagement with pin 3i. It will be noted that the movement of the armature to its pole face at this 3| has dropped to the position in Figure 6 in which it has no biasing action.

' The unlatched condition of link 533 now enables it to be again operated to rotate link 36 in a clockwise direction until the movable contact arm 3? has moved contact 35 in the engaged position shown in Figure 1, and the circui breaker is restored to closed position.

It will now be clear that the present invention provides an arrangement in which, in response to a failure of voltage on the line, the circuit breaker is tripped open and locked open. The opening of the circuit breaker partially restores the armature IE to reduce its air gap suificiently so that it may, against the biasing action of its opening spring Hi and il be restored to full engagernent with the pole face of its electromagnet it when normal line voltage is restored, the latter action resulting in automatic unlatching ofthe circuit breaker.

These functions are achieved by providing a bias spring 41 for the armature i2 which extends from the pin 3! in turn a part of the movable contact mechanism, links 33, 36 and 37 to contact 38. Thus this armature bias isprovided only when the circuit breaker is closed. When the circuit breaker contacts open, the armature bias is withdrawn, as pin 3! drops to the position shown in Figure 6 so that the armature is free to be oper ated against the pole face of magnet it without the biasing action of the spring 51.

In the above I have illustrated a preferred form of my invention and I desire to be limited only by the appended claims.

I claim:

1. In an undervoltage circuit breaker having a pair of cooperable contacts, an electromagnet responsive to voltage conditions or the circuit protected by the circuit breaker, an armature for said electromagnet, a trip mechanism for effecting disengagement of said contacts and operable by said armature in response to de-enersization of said magnet to efiect disengagement of said contacts, a latch mechanism operable in response to disengagement of said contacts for latching said contacts into disengaged position, a member controlled by the complete movement of said movable contact to open position for operating said armature to re-set it close to the pole face of said magnet preparatory for energization of said magnet, and an operating member controlled by said armature in response to the re-energization of said electromagnet for operating said latching mechanism out of engagement with said latch to permit re-operation of said contacts to engaged position.

2. In an undervoltage circuit breaker having a fixed and a movable contact, an electromagnet responsive to the voltage-of the line protected by said circuit breaker, an armature controlled by said electromagnet, a latch for said movable contact operated in response to the operation of said armature to its de-energized position for permitting disengagement of said contacts, a latching mechanism controlled by said armature and operable on movement of said movable contact to its open position for locking said movable contact in its open position, and a member 0011- trolled by the opening of said contacts for resetting said armature close to its pole face in preparation for the re-energization of said electromagnet.

3. In an undervoltage circuit breaker having a fixed and a movable contact, an electromagnet responsive to the voltage of the line protected by said circuit breaker, an armature controlled by said electromagnet, a latch for said movable contact operated in response to the operation of said armature to its de-energized position for permitting disengagement of said contacts, a latching mechanism controlled by said armature and operable on movement of said movable contact to its open position for locking said movable contact in its open position; and a member controlled by the opening of said contacts for resetting said armature close to its pole face in preparation for the re-energization of said electromagnet and for simultaneously disengaging said last mentioned latch mechanism.

CHARLES J. YARRICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,492,138 Meyer Apr. 29, 1924 1,512,064 Sundhaussen Oct. 21, 1924 2,295,309 Thumim Sept. 8, 1942 FOREIGN PATENTS Number Country Date 13,590 Great Britain Nov. 23, 1905 447,748 Germany July 30, 1927 448.271 France 1. Nov. 21. 1912 

